Beneficiated water reducing compositions

ABSTRACT

Exemplary compositions comprise at least one aldopentonic acid, such as xylonic acid; and further comprise a lignin, a lignosulfonic acid or its salt, an additional sugar acid such as a aldohexonic acid or salt, a conventional admixture (such as a polyacrylate superplasticizer, a corrosion inhibitor, a set retard, a set accelerator, etc.), or a mixture thereof. Exemplary methods for obtaining microbiologically or enzymatically converted sugar acids are also described herein.

FIELD OF THE INVENTION

The present invention relates to compositions for modifying hydratablecementitious materials, and more particularly to compositions containingan aldopentonic acid or salt thereof, and optionally comprising alignosulfonate, an aldohexonic acid or its salt, or mixtures thereof,and processes for making these compositions.

BACKGROUND OF THE INVENTION

Various additives have been known to increase flowability (otherwisetermed “slump”) in cementitious compositions, such as mortar andconcrete, without increasing the water content of the initially formedcomposition. Such additives, or “admixtures” as they are also called,are classified as “water reducers” or “superplasticizers” when used forthis purpose. One of the most commonly used of these water reducers arelignin-sulfonate compounds, also called “lignosulfonates,” obtained fromsulfite pulping processes wherein cellulose is extracted from wood.

The so-called sulfite pulping process involves mixing sulfur dioxide(SO₂) with an aqueous solution of base to generate the raw liquor forcooking the wood. In water, the sulfur dioxide forms sulfurous acid(SO₂+H₂₀<--->H₂SO₃) which degrades and eventually sulfonates the ligninby replacing a hydroxyl group with a sulfonate group, allowing it to besolubilized and separated from the cellulose in non-precipitated form.The result is called “spent sulfite liquor” (SSL) and containslignosulfonate and sugars, primarily monosaccharides, that need to beremoved or destroyed so as to permit the lignosulfonate to be usedeffectively as a water-reducing concrete additive. Otherwise, high sugarlevels accompanying the lignosulfonate can significantly retard thesetting of the concrete to the point at which substantial delay ofinitial set time outweighs the water reduction advantage. If notremoved, sugars are usually destroyed (e.g., through degradation,decomposition, etc.) and confer no appreciable benefit to the operationof lignosulfonate in concrete.

One of the objectives of the present invention is to providecompositions containing a lignin and/or lignosulfonate by converting,into useful acid or salt form, the aldose sugars that are present inagricultural residues (e.g., plant, tree, and other cellulose-containingmaterials). The present inventors believe that aldonic acids haveexcellent cement dispersing capabilities, and can therefore“beneficiate” the function of lignosulfonates, in particular, as waterreducing additives.

Another objective of the present invention is to avoid, during recoveryof lignin or lignosulfonate from agricultural materials, the very stepof removing or destroying sugars and the attendant expense. Removedsugars are used as sweeteners. The sugars are typically removed byyeast. Sugars are otherwise destroyed through alkaline oxidation intosmall organic acids and carbon dioxide and water. Instead of removing ordestroying the sugars, however, the present inventors propose to convertthem, using enzymatic or microbiological means that are environmentallyfriendly and efficient. The sugars in the crude lignosulfonates can bealdoses, such as pentose and hexose.

Another and no less significant objective of the present invention is toconvert aldopentose sugars into compositions that are rich inaldopentonic acids (or their salts), and, in particular, compositionsthat are rich in xylonic acid. Other exemplary compositions furthercomprise an aldohexonic acid or its salt (e.g., gluconicacid/gluconate). The present inventors surprisingly discovered thatxylonic acid (or its salt form), which may be obtained through oxidationof xylose sugar, provides lower set retardation than gluconic acid orgluconates, which previously were known as water reducers in theconcrete industry, at equal dosage levels. A preferred composition ofthe invention comprises a converted sugar in a ratio (aldopentonicacid/salt to aldohexonic acid/salt by weight) of 20:1 to 1:10.

A still further objective of the present invention is to provide aprocess that, while producing aldonic acid-beneficiatedlignosulfonate-containing compositions, can be used for adding sugarsfrom other sources (e.g., corn syrup, molasses), so that these can beconverted as well into useful byproducts for modifying one or moreproperties of a hydratable cementitious material.

SUMMARY OF THE INVENTION

In surmounting the disadvantages of the prior art, the present inventionprovides compositions for modifying one or more properties of hydratablecementitious materials, and discloses processes for making suchcompositions.

An exemplary composition of the invention comprises: (A) a lignosulfonicacid or salt thereof; an aldohexonic acid or salt thereof; an hexuronicacid or salt thereof; an hexaric acids or salt thereof; or mixturethereof; and (B) at least one aldopentonic acid or salt thereof.

Another exemplary composition comprises: a lignosulfonic acid or itssalt (e.g., a lignosulfonate); and at least one aldopentonic acid (e.g.,xylonic acid) or salt thereof, and optionally an aldohexonic acid (e.g.,gluconic acid) or salt thereof.

Exemplary processes of the invention for making such a compositioninvolve subjecting agricultural residues—such as corn fibers (such ascobs, stalks, and/or husks), bagasse, straw, bamboo, rice hulls, wheatchaff, hard wood chips, hard wood sawdust, newsprint or recycled paper,or a mixture thereof—to microbially or enzymatically oxidativeprocesses. The products of oxidation provide water-reducing compositionsfor use in cementitious materials, such as concrete, while avoidingexcessive retardation. This is because the preferred process forobtaining such byproducts does not destroy aldose sugars or remove themfrom agricultural residues, but instead allows them to be processed insitu with lignin and/or other biomass sources of aldose sugar (asprovided in hemicellulose hydrolysate liquors) and/or lignosulfonate (asprovided in spent sulfite liquor).

In further exemplary embodiments, higher yields of desired aldonic acidbyproducts may be increased by optionally introducing additional aldosesugars (e.g., corn syrup, molasses from external sources) into theoxidative processing of the agricultural residues. Accordingly, anexemplary process of the invention comprises introducing a microorganismor enzyme which is operative to convert aldose sugars into aldonic acidsor salts, into (A) a hemicellulose hydrolysate (HH) liquor comprisingprimarily at least one aldose or aldourose, preferably including atleast one aldopentose sugar; (B) a spent sulfite liquor (SSL) comprisinga lignosulfonate and at least one aldose sugar (e.g., preferably analdopentose sugar); or (C) a liquor mixture of (A) and (B); andobtaining at least one aldonic acid or salt thereof. The presentinvention is thus further directed to compositions (e.g., lignosulfonicacids or salts in combination with aldonic acids, such as gluconic acid,xylonic acid, their salts, or mixtures thereof) produced through suchprocesses.

Further exemplary processes further comprise introducing said sulfiteprocess liquor, after conversion of aldose sugars into aldonic acids,into a hydratable cementitious composition.

The present inventors surprisingly discovered that xylonic acid providesuseful water reducing ability in hydratable cementitious materials but,at certain dosage levels, without the disadvantageous set retardingquality of gluconates. Xylonic acid and its derivatives have a furtheradvantage in that they do not give rise to air entrainment problems. Nowidespread or economically advantageous process is commercialized atpresent for producing xylonic acid. However, the present inventorsrealize that certain agricultural residues, such as corn stover, canprovide a large xylose source for oxidative conversion into xylonicacid, and these particular agricultural residues have little or nolignin content.

Thus, the present invention also claims compositions comprising xylonicacid and which optionally contains one other conventional admixtures,such as a water reducer (e.g., lignosulfonate), superplasticizers (e.g.,polycarboxylate-type), water repellent agents, corrosion inhibitingagents, shrinkage cracking agents, and others.

In further exemplary compositions of the invention, the pentose sugarcomponent is predominantly xylonic acid or its salt, and thus exceeds inamount arabinonic acid or its salt (if any). Thus, in such furtherexemplary compositions the amount of xylonic acid/salt to arabinonicacid/salt is preferably in the ratio of 1:0 to 1:1. Further advantagesand features of the invention are described hereinafter.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1(a) is a flow chart illustrating a PRIOR ART process for makinglignosulfonates from cellulosic materials;

FIG. 1(b) is a flow chart illustrating a PRIOR ART process for makinghemicellulose hydrolysate products such as ethanol;

FIG. 2(a) is a flow chart illustrating an exemplary process of thepresent invention for making sugar acid products useful for modifyinghydratable cementitious materials;

FIG. 2(b) is a flow chart illustrating another exemplary process of thepresent invention for making sugar acid products useful for modifyinghydratable cementitious materials;

FIG. 3 is a graphic illustration of various combinations oflignosulfonates with or without sugar components;

FIG. 4(a) is a graphic illustration of mortar workabilitycharacteristics of four samples of lignosulfonate compositions;

FIG. 4(b) is a graphic illustration of set time for four differentlignosulfonate compositions in a cementitious mixture;

FIGS. 5 and 6 are graphic illustrations of set time for various dosagesof sodium gluconate and xylonic acid in different cementitious mixes;

FIG. 7 is a graphic illustration of slump for different water reducingadditives at various dosages;

FIG. 8 is a graphic illustration of set time for various dosages ofwater reducing additives;

FIG. 9 is a graphic illustration of alkaline consumption during themicrobial bioconversion of non-desugared SSL;

FIG. 10 is a graphic illustration of the xylose to xylonic acidconversion progress during the microbial bioconversion of non-desugaredSSL determined by HPLC;

FIG. 11 is a graphic illustration of mortar testing workability resultsof the bioconverted SSL;

FIG. 12 is a graphic illustration of mortar testing set time results ofthe bioconverted SSL;

FIG. 13 is a graphic illustration of cement paste test flowabilityresults of the bioconverted SSL;

FIG. 14 is a graphic illustration of cement paste test calorimetricsetting time results of the bioconverted SSL; and

FIG. 15 is a graphic illustration of set time behavior of an exemplarycomposition of the invention comprising xylonic acid andtriethanolamine; and

FIG. 16 is a graphic illustration of set time behavior of an exemplarycomposition of the invention comprising xylonic acid anddiethanolisopropanolamine.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

A first exemplary composition of the invention comprises alignosulfonate and at least one aldopentonic acid or salt, andoptionally at least one aldohexonic acid or salt, which composition isuseful for modifying a hydratable cementitious material. The initialportion of this detailed description section focuses on lignin-basedprocesses, whereby a lignosulfonate appears in the resultantcomposition. Lignin is the characteristic binding constituent betweenthe cell walls of cellulosic materials, such as trees and plants, andprovides an appropriate starting point for present purposes. However, inlatter portions of this detailed description section, the presentinventors focus on processes whereby substantially pure aldopentonicacid/salts (without lignin or lignosulfonate) can be produced usingprocesses of the invention, and used to make custom blended additivesand admixtures for use in modifying cements and concretes.

A lignocellulosic biomass is subjected to acid hydrolysis in a digesterto render a nonsoluble portion, such as cellulose, which can beseparated for making paper products such a papper, and a soluble portionwhich is the hydrolysate liquor that contains lignin and hemicellulose.Hemicellulose contains sugars and sugar polymers, e.g., monosaccharides,oligosaccharides, and polysaccharides. In lignosulfonate production, theprocess is similar except that the hydrolysate is cooked at a hightemperature with sulfite such that the lignin is sulfonated (therebyproducing lignosulfonate) and the hemicelluloses are decomposed tomonosaccharides.

FIGS. 1(a) and 1(b) illustrate prior art processes for convertinglignocellulosic materials (e.g., wood, grass, crop wastes, waste paper)into useful products. FIG. 1(a) illustrates the prior art acid sulfitepulping process, and FIG. 1(b) illustrates a prior art process employingdilute acid hydrolysis. In both processes, typically the sugarbyproducts are fermented into ethanol by yeast, or they are separatedand processed into sweetener products (for human or animal consumption).

In the process of FIG. 1(a), wood and other lignocellulosic materialsare processed in a digester that contains acid sulfite. The insolublematerial of such a process contains cellulosic fibers that are removedand used for making paper and paper products; while the soluble portioncontains sulfonated lignin (lignosulfonate) and monosaccharides.

In exemplary processes of the present invention, however, as illustratedin FIG. 2(a), the inventors propose to avoid removing or destroyingaldose sugars contained in agricultural residues by allowing theminstead to be processed in situ with the lignosulfonate to convert thealdoses into aldonic acids. The resulting aldonic acids, by themselvesor in combination with lignosulfonate, are found by the presentinventors to provide water reducing abilities when incorporated intohydratable cementitious compositions.

As mentioned above, FIG. 1(b) illustrates prior art processes whereinlignocellulosic materials (cellulose, hemicellulose) are converted bydilute acid hydrolysis into hemicellulose hydrolysate which containssugars, and this hydrolysate is usually fermented to provide ethanol.Hemicellulose, a polysaccharide, is the non-cellulosic component ofplant fibers. One type of hemicellulose is xylan, which is a polymer ofpredominantly D-xylose and a small amount of other sugars and sugaracids. Dilute acid hydrolysis of the lignocellulosic materials andsubsequent removal of the insoluble cellulose and lignin leaves thesoluble hemicellulose hydrolysate, which contains predominantly monomers(and oligomers) of the D-xylose and other sugars (as well as somevarious aromatic compounds from the lignin). Typically, thehemicellulose hydrolysate is fermented, using yeast or microbes, toobtain ethanol (See FIG. 1(b), bottom).

In the present invention, an exemplary method of which is illustrated inFIG. 2(b), the present inventors propose to employ the hemicellulosehydrolysate, especially when extracted from angiosperm species andhardwoods, as a precursor for bio-converting aldose sugar content intoaldonic acids (or their salts), especially aldopentonic acids or salts,which provide reducing capabilities when used in hydratable cementitiousmaterials such as concrete and mortar.

An exemplary process of the present invention comprises introducing amicroorganism or enzyme, which is operative to convert aldopentosesugars into aldonic acids or salts, into (A) a hemicellulose hydrolysateliquor comprising a lignin and at least one aldopentose sugar; (B) aspent sulfite liquor comprising a lignosulfonate and at least onealdopentose sugar; (C) or a liquor mixture of (A) and (B), and, afterconversion of aldopentose sugar(s), obtaining at least one aldonic acidor salt thereof.

In order to obtain a composition that is rich in aldopentose sugars thatcan be converted into aldopentonic acids or salts, such as xylonic acid,the hemicellulose hydrolysate liquor and/or spent sulfite liquor must bederived from “agricultural residue” materials that have high aldopentosecontent or their precursors.

Preferred “agricultural residues” useful in processes of the presentinvention therefore include selected plant and tree materials andbyproducts, including, without limitation: corn milling waste (such ascorn stalks, corn husks, corn cobs, corn steep liquor); bagasse (sugarcane or grape residues); rice hulls; wheat chaff (debris separated fromthe seed); grasses (e.g., alfalfa, esparto grass, napier grass, etc.);cereal straws; sorghum; hardwood (e.g., birch, maple, eucalyptus, etc.);bamboo; recycled newsprint or other brown papers having at least a 1 to100% hardwood content by weight.

Other exemplary agricultural residues useful in the present inventionshould be preferably chosen such that substantially little or no ligninor lignosulfonate is present in the byproduct after acid hydrolysis. Forexample, corn stover is believed to be rich in aldopentonic sugar(xylose) but has little or no lignin content. Another preferredagricultural residue is sugar cane, which is believed to have little orno lignin.

Aldose sugars in such agricultural residue materials can be convertedmicrobiologically or enzymatically to organic acids, sugar alcohols, orsolvents (e.g., ethanol). Aldonic acids are sugar acids formed byoxidation of aldoses. In the literature, production of aldonic acidsfrom aldoses through oxidative metabolism, may be achieved usingmicroorganisms such as Gluconobacter, Pseudomonas, and Acetobacter, forexample. These and others have been remarked in the literature:

-   -   Acetobacter sp. (Berhauer, K. and Riedl-Tumova, E. (1950),        Biochem. Z. 321, pp. 26-30).    -   Aspergillis (noted in U.S. Pat. No. 5,620,877 of Farone).    -   Aureobasidium pullulans (noted in German Patent 4317488 of        Anastassiadis).    -   Clostridium sp. (noted in U.S. Pat. No. 5,620,877 of Farone).    -   Enterobacter cloacea (Ishizaki, H., Ihara, T., and Yoshitake, J.        1973), Nippon Nogei Kagaku Kaishi 47, pp. 755-761.    -   Erwinia sp. (Suzuki et al., Agric. Biol. Chem. 29 (1965), pp.        462-470; Uchida et al., Nippon Nogei Kagaku Kaishi 49 (1975),        pp. 257-262).    -   Fusarium lini (Hayasida et al., Biochem. Z. 298 (1938), pp.        169-178); Micrococcus sp. (Ohsugi et al., Agric. Biol. Chem. 34        (1970), pp. 357-363).    -   Gluconobacter Oxydans (Buchert, J., “Biotechnical Oxidation of        D-xylose and Hemicellulose Hydrolyzates by Gluconobacter        Oxydans,” Technical Research Centre of Finland, Publications 70        (Espoo, November 1990), pp. 17-20).    -   Lactobacillis (noted in U.S. Pat. No. 5,620,877 of Farone).    -   Micrococcus sp. (Ohsugi et al., “Oxidative Dissimilation by        Micrococcus sp. Of D-xylose into D-xylonic Acid”)    -   Penicillium corylophilum (Ikeda et al., Nippon Nogei Kagaku        Kaishi 39 (1963), pp. 514-517);    -   Pichia quercuum (Suzuki et al., Appl. Microbiol. 25 (1973), pp.        850-852);    -   Propioni bacteria (noted in U.S. Pat. No. 5,620,877 of Farone);    -   Pseudomonas sp. (Lockwood et al., G. E. N. J. Bacteriol. 52        (1946), pp. 581-586; See also Yokosawa et al., Nippon Nogei        Kagaku Kaishi 26 (1952), pp. 415-420);    -   Pseudomonas fragi (J. Buchert et al., “Production of Xylonic        Acid by Psuedomonas Fragi,” Biotechnology Letters, Vol. 8, No. 8        (1986), pp. 541-546.).    -   Pullularia pullulans (Kiessling et al., Acta Chem. Scand. 16        (1962), pp. 1858-1862); Sasaki et al., J. Ferment. Technol. 48        (1970), pp. 368-373).    -   Zymomonas mobilis (noted in U.S. Pat. No. 5,620,877 of Farone);        This foregoing list is not intended to be exhaustive. Preferred        microorganisms for oxidative digestion of aldoses include        Gluconobacter oxydans, Pseudomonas fragi, and Pullularia        pullulans.

Alternatively, production of aldonic acids from aldoses throughenzymatic conversion may be achieved using aldose oxidase enzymes, suchas, for example glucose oxidase (EC 1.1.1.118; EC 1.1.1.119; EC1.1.1.47; EC 1.1.3.4; EC 1.199.10; EC 1.1.99.17); xylose oxidase (EC1.1.1.175; EC 1.1.1.179; EC 1.1.3.5); or aldose oxidase (EC 1.1.1.121).

Compositions useful for modifying one or more properties of hydratablecementitious compositions thus comprise at least one aldopentonic acidor salt derived from an aldopentose (e.g., xylose, arabinose) and,optionally, an aldohexose (e.g., glucose, galactose, mannose). Thepreferred aldopentonic acid/salt is xylonic acid. The oxidation can beaccomplished by combining one of the aforementioned microorganisms andaldose into an aqueous suspension, optionally but preferablysupplemented by molasses, corn syrup, or glucose, to provide fuel forthe oxidative metabolism as may be required by the microorganism, and/orby combining the aldose and one or more oxidase enzymes into an aqueoussuspension.

A sample description of methods for converting glucose into gluconicacid via enzyme may be found in U.S. Pat. No. 5,897,995 of Vroemen etal.; while methods of glucose conversion via microbial activity may befound in German Patent No. DE 4317488 of Anastassiadis et al., all ofwhich are incorporated herein by reference. Methods of xylose conversionthrough microbial activity using pure xylose and in hemicellulosehydrolysates may be found in Buchert, J., “Biotechnical Oxidation ofD-xylose and Hemicellulose Hydrolyzates by Gluconobacter Oxydans,”Technical Research Centre of Finland, Publications 70 (Espoo, November1990), also incorporated herein by reference.

Preferably, the microbial oxidation is accomplished by introducing atleast one of the microorganisms as described above into a sulfiteprocess liquor that has been separated from cellulose as a result of thesulfite pulp mill processing of agricultural residue such as hard wood.The sulfite process liquor thus contains monosaccharides andlignosulfonate. Instead of removing the monosaccharides, however, thepresent inventors believe that the sulfite process liquor can be used asa source for aldose sugars that can be microbially oxidized into aldonicacids and incorporated directly into a hydratable cementitiouscomposition as a water-reducing additive (thereby “beneficiating” theprocess liquor by avoiding the excessive set retarding properties ofotherwise unconverted sugars). The sulfite process liquor may also besupplemented further with additional aldoses or aldonic acids to furtherbeneficiate the process liquor.

Thus, an exemplary process of the invention comprises introducing, intoa sulfite process liquor derived from pulp milling of hardwood andcontaining aldose sugars inherent in the sulfite process liquor and/orsupplemented aldose sugars, a microorganism or enzyme operative tometabolize the aldose sugars into aldonic acids. Optionally, softwoodcan be incorporated along with the hardwood.

Accordingly, an exemplary composition for modifying one or moreproperties of hydratable cementitious materials, comprises (A) alignosulfonic acid or salt thereof; an aldohexonic acid or salt thereof;an hexouronic acid or salt thereof; an hexaric acids salt thereof; ormixture thereof; (3) at least one aldopentonic acid or its salt.Preferably, the component (A) is present in an amount of 5-90%, morepreferably 5-70% (the percentages herein being based on dry weightsolids in the composition). For example, an exemplary compositioncomprises a lignosulfonic acid or salt; an aldopentonic acid or itssalt; and optionally an aldohexonic acid or its salt.

In another exemplary process, a sugar source such as glucose, cornsyrup, and molasses may be incorporated into the HH or SSL liquor beforeconversion of aldopentose sugars. This may be done, for example, toprovide further sugar acid byproducts and/or to provide metabolic fuelfor the microorganism. For example, glucose may be incorporated into theHH liquor, the SSL liquor, or into a xylose broth (for agriculturalwastes such as corn stover which do not have lignin) to facilitatebio-conversion of the aldopentose into aldonic acids/salts, becausecertain microorganisms require glucose for metabolic support. In“Biotechnical Oxidation of D-xylose and Hemicellulose Hydrolyzates byGluconobacter Oxydans,” Technical Research Centre of Finland,Publications 70 (Espoo, November 1990), Buchert noted that Gluconobacteroxydans sub oxydans required 5% glucose added to xylose for metabolicsupport. Accordingly, the present inventors believe that combinations ofaldopentose and aldohexose sugars may provide better oxidativeenvironments for microbial conversion in some cases.

Further exemplary compositions may comprise an alcohol, such as methanoland ethanol, preferably in an amount of 0-5%, and more preferably0.01-2.0% based on dry weight of solids in the composition.

Still further exemplary compositions may comprise cellulosic fibers inan amount of 0-50%, and more preferably 0.01-2.0% based on dry weight ofsolids in the composition.

The aldopentonic acid or salt of component (B) may comprise arabinonic,xylonic acid, or mixture thereof, but preferably xylonic acid. Asmentioned above, xylonic acid is preferably present in the compositionin the amount of at least 10%, more preferably at least 30%, and mostpreferably at least 50% based on dry weight solids. Further compositionscomprise at least one aldohexonic acid, which may be gluconic acid,mannonic acid, galactonic acid, their salts, or mixtures thereof.

Exemplary cementitious compositions of the invention have at least onehydratable cementitious binder and at least one aldopentonic acid, suchas xylonic acid or its salt, optionally with a lignosulfonic acid or itssalt, an aldohexonic acid or its salt, or mixture thereof. Suchcementitious binder-containing composition may further comprise fineand/or coarse aggregate. The present invention also provides a methodfor modifying a hydratable cementitious composition by introducing atleast one aldopentonic acid or salt to the cementitious binder, such asduring an intergrinding operation whereby the clinker is being ground toobtain a hydratable cement; or such as by combining the aldopentonicacid or salt with a hydratable cement binder before, during, or afterwater is added to hydrate the cementitious binder.

The present invention also provides hydratable cementitious materialshaving the aforementioned lignosulfonic acid or salt with at least onealdopentonic acid or salt thereof. The terms “cement” and “cementitiouscomposition” (which may be synonymous with “cement composition”) may beused herein to refer to dry powders as well as to pastes, mortars,shotcrete, grouts such as oil well cementing grouts, and concretecompositions comprising a hydratable cement binder. The terms “paste”,“mortar” and “concrete” are terms of art: pastes are mixtures composedof a hydratable cement binder (usually, but not exclusively, Portlandcement, plaster, masonry cement, or mortar cement and may also includelimestone, hydrated lime, fly ash, granulated blast furnace slag,pozzolans, silica fume, metakaolin, or other materials commonly includedin such cements) and water; mortars are pastes additionally includingfine aggregate (e.g., sand), and concrete are mortars additionallyincluding coarse aggregate (e.g., crushed gravel, stone).

Cementitious compositions of the present invention may be formed bymixing required amounts of certain materials, e.g., a hydratable cement,water, and optionally a fine aggregate (e.g., sand), coarse aggregate(e.g., crushed stone or gravel), or mixture of both fine and coarseaggregates, as may be applicable to make the particular cementcomposition being formed.

As previously mentioned, the inventors realize that substantially purexylose can be obtained from corn stover without substantial lignincontent and which can be subjected to oxidative degradation throughmicrobial and/or enzymatic conversion. With their discovery that xylonicacid provides advantages as a water reducing additive for cementitiousmaterials with less retardation than gluconic acid at equal dosagelevels, and within the context of the fact that there are no commercialprocesses for producing xylonic acid on a economic or widespread scale,the present invention also provides additive and admixture compositions(for use in cementitious materials) comprising predominantly xylonicacid (or salt), and optionally at least one other component that couldbe added with the xylose before, during, or after it is converted intoxylonic acid.

An exemplary composition therefore comprises xylonic acid in an amountof 10-100% by dry weight solids, optionally one or more materialsselected from a lignosulfonate, an aldohexonic acid (e.g., gluconicacid) or salt thereof, or conventional cement additives and admixtures.Such additives or admixtures may include, for example, a polycarboxylatetype superplasticizer; triethanolamine, triisopropanolamine, an alkalior alkaline earth metal salt (e.g., calcium nitrite, calcium nitrate),or other admixtures, to achieve potentially synergistic benefits.

Accordingly, another exemplary process of the invention comprisesintroducing a microorganism or enzyme, which is operative to convertaldopentose sugars into aldonic acids or salts, into a byproductmaterial obtained by acid hydrolysis of an agricultural residue notcontaining substantial amounts of lignin (e.g., corn stover, corn cob),and obtaining an aldopentonic acid or derivative (e.g., xylonic acid orsalt) having substantially no lignin or lignosulfonate. Consequently,the present inventors believe that substantially pure xylonic acid canbe obtained and used, for example, as a water reducing additive oradmixture for cementitious materials. This process can be modified bycombining sugars from other sources (e.g., corn syrup, molasses,glucose) to obtain customized blends of byproducts before or after theoxidation of the sugars.

The aldonic acid may be combined with other additives r after theconversion of sugars into the sugar acid. Such other additive may, forexample, include one or more of the following materials: molasses,melamine sulfonate formaldehyde polymer, naphthalene sulfonateformaldehyde polymer, alkali or alkaline earth chloride, bromide,protein, alkanolamine, tall oil fatty acid, fatty acid or derivativethereof, fatty ester or derivative thereof, alkali or alkaline earthhydroxycarboxylic acid salt of gluconic acid, glucoheptonic acid, citricacid, tartaric acid, mucic acid, malic acid, salicylic acid,lignosulfonic acid, dye, sucrose, glucose, corn syrup, sodiumsarcosinate, alcohol, phenol, acetic acid, sodium hydroxide, potassiumhydroxide, sodium linear alkylate sulfonate, formaldehyde, silica,diglycinate, polymers containing oxyalkylene groups, calcium formate,formic acid, siloxane, a surfactant, resin and rosin acids, polyacrylicacid, polyvinyl pyrrolidone, aluminate, silicate, carbonate, borate,phosphonate, lactate, sulfate, thiosulfate, benzoate, acetate, oxalate,ferricyanide, and succinate, glycols, borate ester, phosphonate ester,phosphate ester, phenol and derivative thereof, a natural gum, a starch,or derivatives (e.g., salts) of any of the foregoing. Alternatively thealdose sugar and above-mentioned additive may be combined and the aldosesugar subsequently oxidized by the procedures of this invenion,providing the additive is not more easily oxidized than the aldosesugar.

Compositions of the invention comprising xylonic acid or its salt formmay further comprise at least one admixture, such as a set accelerator,retarder, air detrainer, air entrainer, alkali-reactivity reducer,bonding admixture, water-reducing admixture, superplasticizer),colorant, corrosion inhibitor, a damp proofing admixture, gas former,permeability reducer, pumping aid, fungicidal admixture, germicidaladmixture, insecticidal admixture, or a mixture thereof. The foregoingadmixtures are generally known in the art and described, for example, inWorld Patent Application No. PCT/US98/17441 of W. R. Grace & Co.—Conn.,incorporated herein by reference).

Polycarboxylic acid type superplasticizers are conventionally known inthe concrete arts. Exemplary polycarboxylic acid/salt typesuperplasticizers which are contemplated for use in combination with thealdopentonic acid/salt compositions of the invention include so-called“EO/PO type comb polymers,” a term which means and refers to a polymerhaving a backbone such as a carbon backbone to which are attached bothcarboxylate groups (which are believed to function as cement anchoringgroups in the cementitious mixture) and ethylene oxide (EO) groups,propylene oxide (PO) groups, and/or a combination of EO/PO groups in thebackbone of the comb polymer or, more preferably, in pendant groupsattached to the backbone. The pendant groups may be ionic or non-ionic.Examples of EO/PO type comb polymer superplasticizers and water reducersare discussed or described in U.S. Pat. No. 6,352,952 of Jardine et al.,U.S. Pat. No. 5,393,343 of Darwin et al.; as well as in U.S. Pat. No.4,946,904; U.S. Pat. Nos. 4,471,100; 5,100,984; and 5,369,198 whichdescribe comb polymers which are for example copolymers ofpolycarboxylic monomers such as maleic acid or anhydride andpolymerizable EO/PO-containing monomers such as polyalkylene glycolmonoallyl ethers, etc.

A further exemplary composition of the invention comprises at least onealdopentonic acid or salt, such as xylonic acid, and at least oneoxyalkylene-group-containing compound, preferably a polyoxylakylenecompound having repeating ethylene oxide (EO) groups, polyethylene oxide(PO) groups, or a mixture thereof. Such oxyalkylene group containingcompounds, if further having cement-anchoring groups such as carboxylatemoieties, can function as superplasticizers or water reducers, asdescribed above. Such oxyalkylene-group-containing compounds may alsofunction as air entraining agents and/or shrinkage reduction agents.Examples of oxyalkylene type shrinkage reduction agents are disclosed,for example, in U.S. Pat. Nos. 5,556,460 and 5,938,835, which areincorporated herein by reference.

Further exemplary compositions of the invention comprise at least onealdopentonic acid or salt, such as xylonic acid, in combination with atleast two oxyalkylene group containing compositions, such as a firstgroup which is operative to fluidify a cementitious composition, and asecond group which is operative to reduce shrinkage or shrinkagecracking in hydratable cementitious compositions.

Another exemplary composition of the invention comprises at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, incombination with an alkanolamine additive (or admixture), including butnot limited to triethanolamine (TEA); methyl(diethanol)amine:diethanolisopropanolamine (DEIPA); triisopropanolamine (TIPA); tetrahydroxyethyl ethylene diamine (THEED); and other alkanolamines. Thexylonic acid or its salt (“XA”) may be used in an XA:alkanolamineadditive ratio of 100:1 to 1:1 and more preferably 2:1 to 10:1. Forexample, the alkanolamine may be N,N-bis(2-hydroxyethyl)-2-propanolamineor N,N-bis(2-hydroxypropyl)-N-(hydroxyethyl) amine. An exemplarycementitious composition of the invention thus would comprise ahydratable cementitious binder and the XA/alkanolamine additivecombination wherein the amount of the XA present is 0.005 to 0.5% by dryweight based on weight of the cementitious binder.

Another exemplary composition of the invention comprises at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, incombination with an amine additive (or admixture) having at least onehydroxyl group and/or ionic group, including but not limited tosarcosine and glycine. The xylonic acid or its salt (“XA”) may be usedin an XA:amine additive ratio of 100:1 to 1:1 and more preferably 10:1to 3:1. An exemplary cementitious composition of the invention thuswould comprise a hydratable cementitious binder and the XA/additivecombination wherein the amount of XA present is 0.005 to 0.5% by dryweight based on weight of the cementitious binder.

Another exemplary composition of the invention comprises at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, incombination with an additive (or admixture) selected from the groupconsisting of an alkali or alkaline earth hydroxycarboxylic acid salt ofgluconic acid, glucoheptonic acid, citric acid, tartaric acid, mucicacid, malic acid, and salicylic acid. The xylonic acid or its salt(“XA”) may be used in an XA:additive ratio of 1:99 to 99:1 and morepreferably 3:10 to 10:3. An exemplary cementitious composition of theinvention thus would comprise a hydratable cementitious binder and theXA:additive combination wherein the amount of XA is 0.005 to 0.5% by dryweight based on weight of the cementitious binder.

Another exemplary composition of the invention comprises at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, incombination with an additive (or admixture) selected from the groupconsisting of an alkali, alkaline earth, Group III, or transition metalchoride and/or bromide. The xylonic acid or its salt may (“XA”) be usedin a XA:additive ratio of 1:20 to 500:1 and more preferably 1:5 to 10:1.An exemplary cementitious composition of the invention thus wouldcomprise a hydratable cementitious binder and the XA:additivecombination wherein the amount of the XA present is 0.005 to 0.5% by dryweight based on weight of the cementitious binder.

Another exemplary composition of the invention comprises at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, incombination with an additive (or admixture) selected from the groupconsisting of an alkali, alkaline earth, Group III, or transition metalsalt (or acid or derivative thereof) of an aluminate, silicate,carbonate, borate, phosphonate, lactate, sulfate, thiosulfate, benzoate,acetate, oxalate, ferricyanide, succinate, or mixture thereof. Thexylonic acid or its salt (“XA”) may be used in a XA:additive ratio of1:100 to 100:1 and more preferably 1:20 to 20:1. An exemplarycementitious composition of the invention thus would comprise ahydratable cementitious binder and the XA:additive combination whereinthe amount of XA being present is 0.005 to 0.5% by dry weight based onweight of the cementitious binder.

In a further exemplary composition of the invention, the at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, may becombined with at least one other additive (or admixture) selected fromthe group consisting of a glycol (e.g., polyethylene glycol), aglycerol, borate ester, phosphonate ester, phosphate ester, a phenol orphenolic derivative, a natural gum, a starch-derived compound, ahydrocolloid, or a mixture thereof. The xylonic acid or its salt (“XA”)may be used in a XA:additive ratio of 500:1 to 1:1 and more preferably10:1 to 2:1. An exemplary cementitious composition of the invention thuswould comprise a hydratable cementitious binder and the XA/additivewherein the amount of the xylonic acid or its salt being present is0.005 to 0.5% by dry weight based on weight of the cementitious binder.

In a further exemplary composition of the invention, the at least onealdopentonic acid or salt, such as xylonic acid or salt thereof, may becombined with at least one other additive (or admixture) selected fromthe group consisting of a waterproofing agent (e.g., calcium stearate);a finishing aid (e.g., polyether); an anti-freeze agent (e.g., Canitrate or Ca nitrite); a viscosity modifying agent (e.g., biopolymerS-657 or diutan gum, welan gum); a shrinkage reducing agent (e.g.,oxyalkylene type); a strength enhancing agent (e.g., chloridethiocyanate, alkanolamine); an anti-efflorescent agent (e.g., calciumstearate, calcium stearate dispersion); an expansive agent (e.g.,calcium aluminates); and de-icing agent (e.g., chloride salts, glycol).

The aldopentonic acid-containing compositions and beneficiatedlignosulfonate compositions of the invention, in addition to providingexcellent performance as cement additives and concrete admixtures, arebelieved to have potential other applications. Such compositions arebelieved to have advantages, such as dispersants or fluidity modifiers,when used as additives in: oil well drilling muds; pesticideapplications; carbon black (e.g., ink and pigment dispersant); dyemanufacture; asphalt emulsions; water treatment (e.g., dispersant, scaleinhibitor); lead acid batteries; leather tanning; micronutrients (e.g.,metal chelating agents); industrial cleaners (e.g., dispersants fordirt, metal cleaner); ore beneficiation (e.g., lithium); metal plating;enhanced oil recovery; insulation; and others.

The present invention also pertains to methods and compositions whereinaldopentonic acid- or salt-containing compositions of the invention, asdescribed above, are used as dispersants for noncementitious (i.e.,non-hydratable) particles or particulate matter, such as metal oxides(e.g., titanium dioxide), dyes (e.g., anthraquinone dye, azo dye,aniline dye, stilbene, dye), pigments (e.g., zinc oxide, carbon black),fine silicas (e.g., silica fume, finely granulated silica), talc, clay(e.g., kaolin, bentonite), and other such particulate, particulated, orground minerals, organic, or inorganic materials. Preferably, thedispersions are aqueous in nature. Accordingly, further exemplarycompositions of the invention comprise an aqueous suspension comprisingan aldopentonic acid or salt thereof operative to disperse one or moreof the above-identified minerals or materials in particulate form.

The following examples are provided for illustrative purposes only andnot intended to limit the scope of the present invention.

EXAMPLE 1 Lignosulfonate+Aldonic (Xylonic) Acid

Experiments were performed to demonstrate the benefit of convertingxylose in spent sulfite liquor (SSL). Two lignosulfonate products,available from Fraser Paper, were used in the experiments. One is alignosulfonate with sugars not removed; it contains 34% by weightxylose. The other is a lignosulfonate that was de-sugared (such that ithad neglegible sugar content and could be incorporated into a cement orconcrete without appreciable set retardation). The de-sugaredlignosulfonate was combined with a sugar acid (gluconate or xylonicacid) at a lignosulfonate:sugar ratio of 66:34 (FIG. 3) to make a thirdsample for comparison with the lignosulfonate+xylose (i.e., thenon-desugared) composition. Pure xylonic acid was obtained from OmicronBiochemicals, Inc.

[Mortar Testing]

Mortar flow test of the three lignosulfonate samples andlignosulfonate+gluconate was performed in acccordance with JIS A 5201.The mortar mix proportion was Cement/Sand/Water=460/1350/235,water-to-cement ratio by weight (w/c)=0.51. Type I/II ordinary portlandcement and standard EN-sand were used. Both mortar slump and flow weremeasured and the workability was determined in accordance with theformula[workability, mm]=[slump, mm]+[flow, mm]−100.The workability for the de-sugared lignosulfonate, non-desugaredlignosulfonate, de-sugared lignosulfonate+gluconate, and de-sugaredlignosulfonate+xylonic acid for different dosages are shown in FIG. 4.The combination of the lignosulfonate with xylonic acid had a fluidizingeffect that was greater than the lignosulfonate with xylose, as shown inFIG. 4, thus demonstrating that the lignosulfonate was greatlybeneficiated by the xylonic acid and was more effective as a waterreducing additive for cementitious materials.[Concrete Testing]

The lignosulfonate samples were also tested in concrete in accordancewith ASTM C 192 (Standard Practice for Making and Curing Concrete TestSpecimens in the Laboratory), ASTM C 143 (Standard Test Method for Slumpof Hydraulic-Cement Concrete), and ASTM C 39 (Test Method forCompressive Strength of Cylindrical Concrete Specimens). The propertiesof interest in the testing were 9-minute slump, water-reduction, aircontent of the fresh concrete, initial set-time, and compressivestrength.

Two cements sourced from different geographic locations were used in theconcrete testing and will be designated as ‘Cement A’ and ‘Cement B’.The cement factor (amount per cubic yard of concrete made) used for bothcements was 564 lbs/yd³-concrete. The w/c ratios of the referenceconcretes were 0.546 and 0.541 for Cement A and Cement B, respectively,with a target slump of 152 mm (6 inches) at 9 minutes (using thestandard slump cone method as described in ASTM C 143). Thewater-to-cement ratio to achieve the same slump level of the concretehaving a typical lignosulfonate at the dosage of 0.2% solids on cementadmixed into the concrete were found to be 0.532 and 0.502 for Cement Aand Cement B (ie., a 3.6% and 7% water-reduction from the referenceconcretes, respectively).

Table 1 sets forth the concrete testing results involving thelignosulfonate samples as described above. The mixture containing thede-sugared lignosulfonate+xylonic acid required a dosage that was 30-45%less than lignosulfonate alone to obtain the same slump with shortersetting time. The observed superior 2-day strength of the xylonic acidmixture is likely due to shorter set-time. In cementitious systems,longer set times typically yield higher 28-day strength; however, thexylonic acid mixture also demonstrated superior compressive strengthsfor 28-day strength in spite of it having shorter initial set-time. Allthe results confirmed that the water reducing ability of thelignosulfonates was beneficiated by xylonic acid. TABLE 1 Initial 2-day7-day 28-day DOSE SLUMP AIR Set time strength strength strength (% s/s)(mm) (%) (hh:mm) (MPa) (MPa) (MPa) Cement A Reference — 133 1.8  6:0919.6 33.8 41.2 De-sugared 0.2 140 2.2 10:42 18.5 34.6 43.2lignosulfonate Non-de-sugared 0.2 121 2.2 13:28 15.6 35.8 41.3lignosulfonate De-sugared 0.14 159 2.3 10:19 19.2 35.7 44.5lignosulfonate + xylonic acid Cement B Reference — 172 2.4  5:35 16.625.6 32.5 De-sugared 0.2 159 2.4  9:15 20.2 34.7 44.2 lignosulfonateNon-desugared 0.2 159 2 11:29 20.8 37.4 47.0 lignosulfonate De-sugared0.11 165 2  8:04 21.1 34.3 42.1 lignosulfonate + xylonic acid

EXAMPLE 2 Xylonic Acid Calorimetry

Xylonic acid was tested in a cement heat calorimeter to study itssetting time behavior. The initial set time was determined by the onsetof the heat peak. Two cements were used for this calorimetric testing,herein referred to as “Cement B” and “Cement C.” Cement B had a lowersoluble alkali content than Cement C.

FIGS. 5 and 6 show the initial setting time results for xylonic acid andgluconate in Cement B and Cement C, respectively. The resultsdemonstrate that xylonic acid has linear set retardation response to itsdosage, in contrast to sodium gluconate. The inventors therefore believethat the retardation characteristic of xylonic acid is beneficial, inthat it can be used to obtain predictable retardation behavior withdosage as compared to gluconic acid/gluconate in cementitious systems.

EXAMPLE 3 Xylonic Acid Produced via Enzyme Process

D-xylose was oxidized to D-xylonic acid using enzymes to demonstratefeasibility of enzymatic conversion and to investigate the waterreducing capabilities of a solution bearing the resulting conversionproduct. The enzymes used for conversion were glucose oxidase (E.C.1.1.3.4) from Aspergillus niger and catalase (E.C. 1.11.1.6), both ofwhich are available from Genencor International under the tradenamesOxyGo 1500 and Fermcolase 1000, respectively.

In a 500-mL jacketed reaction flask, 50 grams D-xylose (fromSigma-Aldrich Chemicals) was dissolved into 525 grams distilled water tomake an 8% sugar solution. The solution was stirred continuously at 350rpm. The jacketed reaction vessel was connected to a circulating waterbath kept at 55° C. Upon xylose dissolution and temperaturestabilization 0.052 gram OxyGo per gram dissolved solids (approx. 68GOU/gram dissolved solid xylose) and 0.015-0.032 gram Fermcolase pergram dissolved solids (approx. 2000-4000 CU/gram dissolved solid xylose)were added. Air was used as the oxygen source and was bubbled into thebroth at a rate of 3 standard cubic feet per hour (scfh).

The reaction was kept at pH 5.2 by the addition of 0.5M NaOH throughoutthe reaction. The NaOH consumption was used to measure progression ofthe reaction. Additional enzyme was added at 0.052 gram OxyGo per gramdissolved solids and 0.015-0.032 gram Fermcolase per gram dissolvedsolids every 3-5 days of the reaction. The reaction was halted when theamount of NaOH consumed corresponded to 90% conversion of xylose sugarto xylonic acid.

The ion chromatography analysis showed that the product contains5.5-9.3% (on dry weight of the product) of chloride which was originatedfrom the enzymes used.

[Concrete Testing]

The xylonic acid prepared above was tested in concrete as in example 1according to ASTM C 192 and ASTM C 143. The 9-min slump values andinitial set times in concrete of the xylonic acid alone were comparedwith those of the de-sugared lignosulfonate, sodium gluconate alone, andD-xylose (the starting material) alone. Cement A was used with a cementfactor of 564 lbs/yd³-concrete and the water-to-cement ratio was 0.567.Various dosages of each sample were tested.

FIGS. 7 and 8 show the results for slump and set time, respectively. Asshown in FIG. 7, xylonic acid performed significantly better in slumpfor a given dosage than de-sugared lignosulfonate, and almost nearly aswell as sodium gluconate alone. FIG. 8 shows that xylonic acid has asignificantly shorter set time than gluconate and a similar set timeperformance compared to de-sugared lignosulfonate. It should be noted,however, that a part of set-time reduction was likely due to thepresence of chloride in this particular sample. The present inventorsnote that the xylonic acid was nearly twice as effective as de-sugaredlignosulfonate, as only about half the amount of the xylonic acid wasneeded to obtain a similar slump in fresh concrete when compared to thede-sugared lignosulfonate. Considering the results of this example withthose of example 2, the present inventors believe that xylonic acid,with its linear set retardation response within the practical dosagerange and its concrete-plasticizing capability, provides a surprisinglybeneficial water reducing ability.

EXAMPLE 4 Xylose Conversion by Gluconobacter oxydans, ATCC 621, in SSL

D-xylose in hardwood spent sulfite liquor (SSL) was bio-converted toD-xylonic acid using a microorganism to demonstrate feasibility ofmicrobial conversion with the presence of lignosulfonate. Themicroorganism used for conversion was Gluconobacter Oxydans suboxidans(ATCC 621). The SSL substrate used was non-desugared lignosulfonate fromFraser Paper described in Example 1.

[Bio-Conversion]

The bio-conversion of SSL was performed according to the followingprocedure based on the literature (Buchert, J., “Biotechnical Oxidationof D-xylose and Hemicellulose Hydrolyzates by Gluconobacter Oxydans,”Technical Research Centre of Finland, Publications 70 (Espoo, November1990), pp. 17-20). The inoculum of G. oxydans was prepared with thebasal medium described in the above literature. A 50 mL of basal mediacontaining xylose and glucose (xylose:glucose=20:1 g/L) in each 250 mLflask was inoculated with G. oxydans (viable counts=10⁵ cfu) andincubate at 25 deg C. on a shaker table (200 rpm). Within 5 days, the pHof the culture media dropped to 3 and the viable counts increased toover 10⁷ cfu. Total 100 mL of the culture media was then spun down to 1mL. Thus prepared inoculum was added to a 100 mL of the sterile hardwoodSSL (5 wt. %) with basal media except xylose and glucose. Thebio-converison was done in a sterilized bio-reactor (500 mL scale)equipped with a mechanical stirrer, filtered air bubbling tube and pHcontroller. The pH was maintained at 5.5 using a NaOH solution. Theconversion was monitored by the consumption of NaOH and HPLC. Theprogress of the conversion are shown in FIG. 9 (NaOH consumption) andFIG. 10 (HPLC).

It was also demonstrated that the conversion rate can be significantlyimproved by simply adding more G. Oxydans in the bio-reactor.

[Mortar Testing]

The obtained bio-converted SSL was tested in mortar as described inExample 1. The mortar mix proportion was Cement/Sand/Water=384/1350/230.The dosage used was 0.1 wt. % of solid on the weight of cement. FIG. 11and FIG. 12 shows the workability and Setting time results,respectively. As shown in the figures, the workability of startingnon-desugared SSL was significantly improved by the bio-conversion.Setting time is similar to the starting SSL, but longer than a desugaredSSL. However, higher workability of the bio-converetd SSL allows to useless amount, and consequently the set-time should be equivalent todesugared SSL.

[Paste Testing]

The bio-converted SSL was also tested against starting SSL and desugaredSSL in the cement paste. The cement paste test was performed with thew/c ratio of 0.5. Delayed addition of chemicals was employed. The pastetest procedure is described elsewhere (e.g. B.-w. Chun, Cement andConcrete Research, 31 (2001) 959-963). FIG. 13 and FIG. 14 show thecement paste flow data and calorimetric setting time data respectively.As shown in FIG. 13, the bio-converted sample shows superiorflowability. According to the result, the required dosage of thebio-convereted SSL to achieve the same workability is substantially lessthan the starting SSL and desugared SSL. The setting time of thebio-converted SSL should be equivalent or even less than the desugaredSSL at the dosages adjusted to the same workability.

EXAMPLE 5

The inventors discovered a synergistic behavior in set time behaviorwhen xylonic acid or its salt was combined in mortar with analkanolamine, such as triethanolamine (TEA) or adiethanolisopropanolamine such asN,N-bis(2-hydroxyethyl)-2-propanolamine orN,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine.

A mortar was prepared using a Type I Portland cement, sand (such thatthe sand to cement weight ratio was 2.935), and water (such that thewater to cement ratio was 0.543). Five different samples were testedhaving an admixture comprising xylonic acid and/or TEA or DEIPA, whereinthe amount of xylonic acid was progressively 0%, 25%, 50%, 75%, and100%. These samples were tested for set time behavior.

The results for xylonic acid and/or TEA are depicted in FIG. 15, whilethe results for xylonic acid and/or DEIPA are depicted in FIG. 16. Fromthese figures, it can be seen that the addition of alkanolaminedecreases the set time for a given xylonic acid percentage in comparisonto what would typically be expected as a matter of normal additiveeffect.

When the workability of the various xylonic acid/alkanolaminecombinations were tested at 0%, 25%, 50%, 75%, and 100% (xylonic acid),however, it was found that the behavior of workability was merelyadditive (ie. the workability tended to increase linearly as thepercentage of xylonic acid was increased). Thus, the behavior shown inFIGS. 16 and 17 were believed to indicate highly synergistic behaviorbetween the xylonic acid and alkanolamines in terms of set timebehavior.

Hence, exemplary compositions of the invention comprise an aldopentonicacid, aldohexonic acid, their salts, or mixtures thereof, in combinationwith an alkanolamine, such as TEA and DEIPA.

The invention is not to be limited by the foregoing examples andpreferred embodiments, which are provided for purposes of illustrationonly.

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 15. Acementitious composition comprising a hydratable cementitious binder andan additive or admixture composition comprising (A) a first componentselected from the group consisting of a lignosulfonic acid or saltthereof and a gluconic acid or salt thereof in an amount no less than 5%and no greater than 90% based on dry weight solids in said additive oradmixture composition; and (B) a second component comprising xylonicacid or salt thereof in an amount no less than 10% and no greater than95% based on dry weight solids in said additive or admixturecomposition.
 16. The cementitious composition of claim 15 wherein saidhydratable cementitious binder comprises Portland cement, masonrycement, mortar cement, limestone, hydrated lime, fly ash, granulatedblast furnace slag, a pozzolan, silica fume, metakaolin, or mixturethereof.
 17. The cementitious composition of claim 16 further comprisingan aggregate comprising sand, gravel, crushed stone, or mixture thereof.18. A method for modifying a hydratable cementitious compositioncomprising: combining with a cementitious material an additive oradmixture composition comprising (A) a first component selected from thegroup consisting of a lignosulfonic acid or salt thereof and a gluconicacid or salt thereof in an amount no less than 5% and no greater than90% based on dry weight solids in said additive or admixturecomposition, and (B) a second component comprising xylonic acid or saltthereof in an amount no less than 10% and no greater than 95% based ondry weight solids in said additive or admixture composition.
 19. Themethod of claim 18 wherein said combining step comprises introducingsaid additive or admixture composition to cement clinker during anintergrinding operation whereby the clinker is being ground to obtain ahydratable cement.
 20. The method of claim 18 wherein said combiningstep comprises introducing said additive or admixture composition tohydratable cement before or after adding water to the hydratable cement.21. (canceled)
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 47. Thecomposition of claim 15 further comprising an alcohol selected from thegroup consisting of methanol and ethanol, said alcohol being present inan amount no less than 0.01%, and said alcohol being present in anamount no greater than 5.0%, said percentages being based on dry weightsolids in the composition.
 48. The composition of claim 15 furthercomprising cellulose fibers being present in an amount no less than0.01%, and said cellulose fibers being present in an amount no greaterthan 5.0%, said percentages being based on dry weight solids in thecomposition.
 49. The composition of claim 15 further comprisingarabinonic acid or salt thereof.
 50. The composition of claim 15 whereinxylonic acid is present in the amount of at least 30% based on dryweight solids in the composition.
 51. The composition of claim 15wherein said xylonic acid is present in the amount of at least 50% wt.based on dry weight solids in the composition.
 52. The composition ofclaim 49 wherein the amount of said xylonic acid or salt thereof exceedsthat of said arabinonic acid or salt thereof.
 53. The composition ofclaim 49 wherein said arabinonic acid or salt thereof is in an amountthat is no greater than 30% by weight of total composition.
 54. Thecomposition of claim 15 comprising a gluconic acid or salt thereof. 55.The composition of claim 54 further comprising a mannonic acid,galactonic acid, or salt or mixture thereof.
 56. The composition ofclaim 54 having an aldopentonic acid or salt content in an amount noless than 0.1% and in an amount no greater than 40% based on dry weightsolids in the composition.
 57. The composition of claim 15 furthercomprising at least one other additive or admixture.
 58. The compositionof claim 57 wherein said additive or admixtures is an alkanolamine. 59.The composition of claim 58 wherein said alkanolamine is selected fromthe group consisting of triethanolamine, a diethanolamine, adiethanolisopropanolamine, a triisopropanolamine, and mixtures thereof.60. The composition of claim 59 wherein said alkanolamine isN,N-bis(2-hydroxyethyl)-2-propanolamine orN,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine.
 61. The composition ofclaim 58 wherein the ratio of said xylonic acid or salt thereof to saidalkanolamine is not less than 1:1 and not greater than 100:1.
 62. Thecomposition of claim 61 wherein said ratio of said xylonic acid or saltthereof to said alkanolamine is 2-10:1.
 63. The composition of claim 51further comprising an additive selected from the group consisting ofmolasses, melamine sulfonate formaldehyde polymer, naphthalene sulfonateformaldehyde polymer, ammonium, alkali, alkaline earth, trivalent, ortransition metal chloride and bromide, protein, alkanolamine, tall oilfatty acid, fatty acid or derivative thereof, fatty ester or derivativethereof, ammonium, alkali, alkaline earth, trivalent, and transitionmetal salts of hydroxycarboxylic acids including gluconic acid,glucoheptonic acid, citric acid, tartaric acid, mucic acid, malic acid,and salicylic acid, salts of lignosulfonic acid, dyes, sucrose, glucose,corn syrup, sodium sarcosinate, alcohol, phenol, acetic acid, sodiumhydroxide, potassium hydroxide, sodium linear alkylate sulfonate,formaldehyde, silica, polymers containing oxyalkylene groups, calciumformate, formic acid, siloxane, a surfactant, resin and rosin acids,polyacrylic acid, polyvinyl pyrrolidone, ammonium, alkali, alkalineearth, trivalent, and transition metal salts of aluminate, silicate,carbonate, borate, phosphonate, lactate, sulfate, thiosulfate, benzoate,acetate, oxalate, ferricyanide, and succinate, glycols, borate ester,phosphonate ester, phosphate ester, phenol and derivative thereof, anatural gum, and a starch.
 64. The composition of claim 51 wherein saidcomposition further comprises an admixture selected from the groupconsisting of an accelerator, retarder, air detrainer, air entrainer,alkali-reactivity reducer, bonding admixture, water-reducing admixture,superplasticizer, colorant, corrosion inhibitor, damp proofingadmixture, gas forming agent, permeability reducer, pumping aid,fungicidal admixture, germicidal admixture, insecticidal admixture,waterproofing agents, finishing aids, anti-freeze agents, viscositymodifying agents, shrinkage reducing agents, shrinkage-compensatingagents, strength enhancing agents, anti-efflorescence agents, expansiveagents, and de-icing agent.
 65. The composition of claim 51 furthercomprising at least one additive or admixture having at least oneoxyalkylene group.